实验topo：

当组网成功时：

多余链路会被阻塞出现备份

原正常链路失效时备份链路被激活

SW1：

vlan batch 10 20 30 40

stp mode mstp
stp enable
stp region-configuration
region-name huawei
instance 1 vlan 10 20
instance 2 vlan 30 40  active region-configuration

stp instance 1 root primary
stp instance 2 root secondary

interface GigabitEthernet0/0/24
port link-type trunk
port trunk allow-pass all  interface GigabitEthernet0/0/21  port link-type trunk
port trunk allow-pass all

interface Vlanif10
ip address 192.168.10.253 255.255.255.0
vrrp vrid 10 virtual-ip 192.168.10.254
vrrp vrid 10 priority 120
vrrp vrid 10 preempt-mode timer delay 20

interface Vlanif20
ip address 192.168.20.253 255.255.255.0
vrrp vrid 20 virtual-ip 192.168.20.254
vrrp vrid 20 priority 120
vrrp vrid 20 preempt-mode timer delay 20

interface Vlanif30
ip address 192.168.30.252 255.255.255.0
vrrp vrid 30 virtual-ip 192.168.30.254

interface Vlanif40
ip address 192.168.40.252 255.255.255.0
vrrp vrid 40 virtual-ip 192.168.40.254

SW2

vlan batch 10 20 30 40

stp mode mstp
stp enable
stp region-configuration
region-name huawei
instance 1 vlan 10 20
instance 2 vlan 30 40  active region-configuration

stp instance 2 root primary
stp instance 1 root secondary

interface GigabitEthernet0/0/24
port link-type trunk
port trunk allow-pass all  interface GigabitEthernet0/0/22  port link-type trunk
port trunk allow-pass all

interface Vlanif10
ip address 192.168.10.252 255.255.255.0
vrrp vrid 10 virtual-ip 192.168.10.254

interface Vlanif20
ip address 192.168.20.252 255.255.255.0
vrrp vrid 20 virtual-ip 192.168.20.254

interface Vlanif30
ip address 192.168.30.253 255.255.255.0
vrrp vrid 30 virtual-ip 192.168.30.254
vrrp vrid 30 priority 120
vrrp vrid 30 preempt-mode timer delay 20

interface Vlanif40
ip address 192.168.40.253 255.255.255.0
vrrp vrid 40 virtual-ip 192.168.40.254
vrrp vrid 40 priority 120
vrrp vrid 40 preempt-mode timer delay 20

SW3